Thread: should switch to fuel injection?

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I've been having nothing but trouble with carburetors. I had an edelbrock 650 on my bb chevy street vehicle (mech secondaries). It is fine when you are cruising or driving very conservatively (easy throttle transitions). If you try and have some fun and get on it real hard and real quick (fast transition) you may as well just forget about it. It will pop super loud and hesitate for a couple seconds and by the time it catches up with itself there's no point in staying on it.
I also had an old holley 750 (vac sec) that I recently got a rebuild kit for. I put it on this weekend and tried it out. It had noticeable more power when accelerating through gears (I have a manual), but between shifts when I got off it seemed kind of strange. But still, if I was at light throttle and tried to get on it real quick it would just dog out and shake.
I am 26 years old and grew up at the tail end of carburetion, so maybe I just take for granted how well fuel injection works because that's all I really knew. . .but I don't think carb's should be this crappy.
Is it possible to have a carbureted engine that does not bog out under rapid throttle transitions or is that a pipe dream?

Absolutely! A properly working carb should respond instantly to all your throttle commands.

You did not mention what is under the carb and as I'm sure you know that is equally important. I'm guessing it's a small block. The 750 Holley is maybe too big for it, but in general a properly working vacuum secondary carb is great on the street. The fact that it was an oulder rebuilt Holley mat also be a problem as the throttle plate and rods can wear and begin leaking when they get older.

Fuel injection is great too, probably outperfroming a carb in every way, again when properly tuned. The thing I don't like about them is cost and clutter. All the wires and control boxes etc really muddle things up under hood and dash IMO ............

Kitz

tcodi- carbs allow us much more room for screwing up, as well as fine tunning the engine. From your post you seem to be hunting for the "magic" carb that will turn your motor into the beast you want it to be. Not going to happen. There are MANY aspect's of tunning in a engine that have to be in sync to get it to perform correctly- timing, cam spec's, CR's, ect. that will allow you to get a proper tune on your carb.
Carb. size by cfm's, for a starting point, I use this formula : CFM's = Total cubic inches x max. RPM rated by the cam spec.'s, divided 3456.
This will give you a starting point for carb. size to work with.
Every carb manufactuer out there prints a manual on proper tunning and adjustments for their carbs. They all try different things to make their's the best so find the book on the make and size covered for your carb. This is the best way to carb heaven.
Good Luck,

it's a big block 402.

yeah, I think I'm gonna sell the edelbrock and use the money to get a holley. I did think that the old holley might be part of the problem because it was almost impossible to get the ancient gasket material off the surfaces when I rebuilt it. That may have screwed it up a bit.
I certainly don't expect this old engine to run perfectly, but right now it is ridiculous.

And a copy of this book will help you tune it.

is there a rule of thumb for secondary action with a manual tranny (mech or vac)?

I've heard different opinions. My edelbrock was mech, the holley tried was vacuum. I ordered a new holley last night, it was kind of unclear as to if it was mech or vac.

Vacuum secondaries are usually recomended with an automatic trans.

Originally Posted by tcodi

is there a rule of thumb for secondary action with a manual tranny (mech or vac)?

I've heard different opinions. My edelbrock was mech, the holley tried was vacuum. I ordered a new holley last night, it was kind of unclear as to if it was mech or vac.

What number Holley?

holley 4160

That's a vacumn secondary carb. What cfm?

I had a camaro with a 396 with the same problem. I had plenty of cam so that was not the issue. I change carbs and still had that problem. What turned out to be my problem was the timing chain had jumped and the timing was off. I could cruise fine and accelerate moderately, but could not floor it. After my timing issues were fixed rubber was burning gain.

750 cfm
sh*t, I've checked over just about every possible thing except that thus far. If it's a mechanical issue, then I think the timing is the only possible one left.
If I need to check that, is it possible to do it with the engine in the car?
My radiator/pulley clearance is virtually non-existant so it would be almost impossible to get a degree wheel on the balancer, or read it if it were on there.
Are there any ways to check that without tearing everything apart?

Unrelated engine. I had this same problem on a 327 I had. I was able to correct it with a simple turn of the distributor. I did not have a timing light then..

I put my new holley on last night. It started up instantly, which was a very pleasant surprise and change from what I'm used to. It had noticeably more power when pulling through the gears, but I still couldn't put the pedal down too fast or it would sound more like a wild west gun fight then a hot rod.
I'm not sure if I just need a bigger acc. pump cam, I bought the cam kit but the thing doesn't tell you which color cams correspond to what pumping level. I tried to eyeball them, but they are pretty close.

Do you have an electronic or a mechanical fuel pump?